Patent GB-344267-A (GB)
Title: Improvements in automotive vehicles
IPC: B60T7/12
Filed: 1930-04-16
Abstract: 344,267. Vehicle brakes. TRIGGS, W. W., 57, Lincoln's Inn Fields, London.- (Warner Electric Brake Corporation ; 449, Gardner Street, South Beloit, Illinois, U.S.A.) April 16, 1930, No. 12029. [Class 103 (i).] Reverse movement, preventing ; applied by running axle ; band ; electric and magnetic.-Motor vehicles are provided with an electro-magnetically controlled brake which is applied automatically upon undesired backward movement of the vehicle and is automatically released upon the application of power to the vehicle for forward propulsion. The automatic action is rendered inoperative when the gear lever is put into reverse and also by the ignition circuit-breaker when the vehicle is parked. The brakes shown are of the kind applied by the momentum of the vehicle and comprise for each wheel a pair of magnetic rings 21, 22 one of which 22 is connected by a series of spring strips 26 to the brake drum 12 so as to rotate therewith while the other, 21, has a winding 23 and is rotatably mounted upon. a fixed part 24. A brake band 13 has its ends normally held against a stop 15 by a spring 14. The spring strips 26 hold the rings 21, 22 in contact and when the winding is energized the ring 21 is carried round to a limited extent by the ring 22 and a projection 25 upon it engages one end or the other of the brake band 13 according to the direction of rotation of the wheel and applies it to the brake drum 12. The circuit for the windings 23 includes a rheostat comprising a number of parallel resistances 30, Fig. 3, one or more of which are connected in as the pedal 34 is depressed, by engagement of a pivoted contact bar 33 with spring contact strips 32, the initial movement connecting the battery 28 through the strip 36. The automatic operation of the brakes is effected by a switch device comprising an arm 55 pivoted at 54 to a casing 54<a> secured to the gear box 50 of the vehicle and adapted to close a pair of contacts 42 carried by spring arms. The arm 55 has frictional engagement with a part which rotates with the propeller shaft 49 of the vehicle and may as shown be the transmission brake drum 58. With the. normal direction of rotation the parts assume the position shown but should the vehicle start running backwardly the arm 55 is moved to the right by the drum 58 and closes the contacts 42 so that the brakes are applied, the circuit being:-battery 28; conductor 47, switch 46 (assumed to be closed), conductor 45, resistance 44, conductor 43, switch 42, conductors 41, 31, 40, and the windings 23. If subsequently the vehicle motor is coupled to the shaft 49 for forward drive, the backlash in the driving gear may be sufficient to cause the drum 58 to reopen the switch 42 and release the brake but if the brake magnets should still remain de-energized sufficient forward movement of the wheel for this purpose is permitted by the play of the projection 25 on the magnet ring 21 between the ends of the brake band. When the gear lever 66 is put in reverse position a stop member 68 is moved into position by the engagement of a lug 69 on the gear rod 70 with a sliding rod 65<a> to prevent movement of the arm 55 from closing the switch 42. To prevent automatic operation of the brakes and waste of current when the vehicle is standing the switch 46 generally included in the ignition circuit for putting the motor out of action and which is actuated by a locking device 73 is included also in the automatic braking circuit.